The present invention relates to a motorcar having a compressed fuel tank charged with a compressed fuel such as natural gas or liquefied petroleum gas disposed in a compartment such as a trunk room, particularly to a structure of a piping for the compressed fuel in the motorcar and a method for inspecting leakage of the piping.
Japanese Laid-Open Patent Publication No. Sho 52-93024 (1977) discloses a motorcar having a compressed fuel tank charged with liquefied petroleum gas (LPG) disposed in a trunk room in which a circumference of the compressed fuel tank, a supporting member of the tank and a pipe connection part of the tank is closed up tightly by a fuel cylinder case and a fuel cylinder case cover so that a fuel gas leaking out from the connection part between the compressed fuel tank and a pipe does not flow into the trunk room.
In the motorcar described in the above Japanese Publication, the fuel cylinder case and the fuel cylinder case cover have to cover the supporting member of the compressed fuel tank as well as the whole of the tank, so that the case and the case cover becomes broad, and also, a length of a edge of the case to be joined to the car body becomes long to necessitate a careful attention for the tight closing up thereof. Moreover, the working time is prolonged necessarily and a high cost is inevitable.
Japanese Laid-Open Patent Publication No. Hei 7-195948 (1995) discloses a structure for sealing a compressed fuel tank piping of a motorcar. In this structure, as shown in FIG. 11, a compressed fuel supply auxiliary unit 02 housing devices necessary for charging a fuel into a compressed fuel tanks 01 and for supplying the fuel from the tanks 01 to an internal combustion engine is covered with a seal case 03 which is supported by a supporting member 06 standing from a floor 05 within a trunk room 04. Pipes 08 extending free from the auxiliary unit 02 are exposed at openings 07 of the seal case 03. Four pipes 08 are connected with valves 09 attached to the compressed fuel tanks 01, and other two pipes 08 are connected with a gas charging pipe 010 and a fuel supply pipe 011 on the outside of the car room, respectively. The fuel supply pipe 011 is connected to an internal combustion engine not shown. So as to cover these pipes 08, both ends of two tubular covers 014 are tightly attached to openings 07 of the seal case 03 and tubular end plates 012 attached to the valves 09 and both ends of another tubular cover 014 are tightly attached to another opening 07 of the seal case 03 and a tubular opening 013 standing from the floor 05.
According to the prior art of the Japanese Publication No. Hei 7-195948, since only parts having a chance of gas leak occurring is covered by the tubular covers 014, a small sealing member can be used and it is not necessary to cover-up to a supporting member of the tank so that the sealing structure is simplified. However, since all connection of the pipes 08 must be carried out within the narrow trunk room, it is difficult to perform the pipe connection work in a short time, efficiently and surely.